Peter Germonpre

Peter Germonpre

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69
Publications
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937
Citations
Citations since 2016
28 Research Items
639 Citations
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140

Publications

Publications (69)
Article
Full-text available
Oxygen is a powerful trigger for cellular reactions, but there are few comparative investigations assessing the effects over a large range of partial pressures. We investigated a metabolic response to single exposures to either normobaric (10%, 15%, 30%, 100%) or hyperbaric (1.4 ATA, 2.5 ATA) oxygen. Forty-eight healthy subjects (32 males/16 female...
Article
Full-text available
Background: Despite evolution in decompression algorithms, decompression illness is still an issue nowadays. Reducing vascular gas emboli (VGE) production or preserving endothelial function by other means such as diving preconditioning is of great interest. Several methods have been tried, either mechanical, cardiovascular, desaturation aimed or bi...
Article
Full-text available
Background: This study aimed to observe the effects of a fast acute ascent to simulated high altitudes on cardiovascular function both in the main arteries and in peripheral circulation. Methods: We examined 17 healthy volunteers, between 18 and 50 years old, at sea level, at 3842 m of hypobaric hypoxia and after return to sea level. Cardiac output...
Article
Full-text available
PurposeData regarding decompression stress after deep closed-circuit rebreather (CCR) dives are scarce. This study aimed to monitor technical divers during a wreck diving expedition and provide an insight in venous gas emboli (VGE) dynamics.Methods Diving practices of ten technical divers were observed. They performed a series of three consecutive...
Article
Full-text available
Impaired flow mediated dilation (FMD), an index of vascular stress, is known after SCUBA diving. This is related to a dysfunction of nitric oxide (NO) availability and a disturbance of the redox status, possibly induced by hyperoxic/hyperbaric gas breathing. SCUBA diving is usually performed with a mask only covering “half face” (HF) and therefore...
Article
Full-text available
Introduction: Divers with a patent Foramen Ovale (PFO) have an increased risk for decompression sickness (DCS) when diving with compressed breathing gas. The relative risk increase, however, is difficult to establish as the PFO status of divers is usually only determined after a DCS occurrence. Methods: This prospective, single-blinded, observation...
Article
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Background: Divers thermal status influences susceptibility to decompression sickness hence the need for proper insulation during immersion in cold water. However, there is a lack of data on thermal protection provided by diving suits, hence this study. Materials and methods: Two different groups of divers wearing either a wetsuit (n = 15) or a...
Article
Full-text available
Inflammation is an adaptive response to both external and internal stimuli including infection, trauma, surgery, ischemia-reperfusion, or malignancy. A number of studies indicate that physical activity is an effective means of reducing acute systemic and low-level inflammation occurring in different pathological conditions and in the recovery phase...
Article
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Introduction: Heart rate variability (HRV) during underwater diving has been infrequently investigated because of environment limitations and technical challenges. This study aims to analyze HRV changes while diving at variable hyperoxia when using open circuit (OC) air diving apparatus or at constant hyperoxia using a closed-circuit rebreather (CC...
Article
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We report Blood Oxygen Level Dependent (BOLD) signal changes recorded in the brain of an elite breath-hold diver during voluntary dry long breath-hold by means of fMRI. An independent component analysis (ICA) method was applied to extract brain areas that are putatively involved in the apnea process network. We discuss the hypothesis that these BOL...
Article
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The term “normobaric oxygen paradox” (NOP), describes the response to the return to normoxia after a hyperoxic event, sensed by tissues as oxygen shortage, and resulting in up-regulation of the Hypoxia-inducible factor 1α (HIF-1α) transcription factor activity. The molecular characteristics of this response have not been yet fully characterized. He...
Article
Venous gas emboli (VGE) are often quantified as a marker of decompression stress on echocardiograms. Bubble-counting has been proposed as an easy to learn method, but remains time-consuming, rendering large dataset analysis impractical. Computer automation of VGE counting following this method has therefore been suggested as a means to eliminate ra...
Article
Full-text available
Introduction: The Azoth Systems O'Dive bubble monitor is marketed at recreational and professional divers as a tool to improve personal diving decompression safety. We report the use of this tool during a 12-day dive trip aboard a liveaboard vessel. Methods: Six divers were consistently monitored according to the user manual of the O'Dive system...
Preprint
Full-text available
Introduction: The SARS-CoV2 pandemic has led to an worldwide shortage of Personal Protection Devices (PPD) for medical and paramedical personnel. Adaptation of commercially available snorkel masks to serve as full face masks has been proposed. Even not formally approved as PPD, they are publicized on social media as suitable for this use. Concerns...
Article
Full-text available
Introduction: The “Severe Acute Respiratory Syndrome Coronavirus 2″ (SARS-CoV2) pandemic has led to a worldwide shortage of personal protection devices (PPD) for medical and paramedical personnel. Adaptation of commercially available snorkel masks to serve as full face masks has been proposed. Even not formally approved as PPD, they are publicized...
Code
As a result of strict preventive measures taken by almost all countries worldwide to combat the spread of SARS-CoV2 and COVID-19 disease, there is a significant impact on the availability of healthcare resources, not only hospital-based but also for emergency first aid and patient transport. Generally, all sports activities are advised against, exc...
Article
Full-text available
Oxygenation conditions are crucial for growth and tumor progression. Recent data suggests a decrease in cancer cell proliferation occurring after exposure to normobaric hyperoxia. Those changes are associated with fractal dimension. The purpose of this research was to study the impact of hyperoxia on apoptosis and morphology of leukemia cell lines....
Article
Our understanding of decompression physiopathology has slowly improved during this last decade and some uncertainties have disappeared. A better understanding of anatomy and functional aspects of patent foramen ovale (PFO) have slowly resulted in a more liberal approach toward the medical fitness to dive for those bearing a PFO. Circulating vascula...
Article
Full-text available
Introduction: The risk for decompression sickness (DCS) after hyperbaric exposures (such as SCUBA diving) has been linked to the presence and quantity of vascular gas emboli (VGE) after surfacing from the dive. These VGE can be semi-quantified by ultrasound Doppler and quantified via precordial echocardiography. However, for an identical dive, VGE...
Article
Full-text available
Introduction: Cognitive impairment related to inert gas narcosis (IGN) is a threat to diving safety and operations at depth that might be reduced by using enriched air nitrox (EANx) mixtures. Using critical flicker fusion frequency (CFFF), a possible early detection of cognitive abilities/cerebral arousal impairment when breathing different oxygen...
Article
Full-text available
In situ evaluation of human brain performance and arousal remains challenging during operational circumstances, hence the need for a rapid, reliable and reproducible tool. Here we hypothesized that the Critical flicker fusion frequency (CFFF) reflecting/requiring visual integration, visuo-motor skills and decision-taking process might be a powerful...
Article
Full-text available
Introduction: Because a significant association between training to perform emergency free ascent (EFA) and the occurrence of pulmonary barotrauma (PBT) was demonstrated in 2006, the Belgian Underwater Federation (BUF) decided to discontinue this procedure. An evaluation was needed 10 yr after the implementation of this change. Methods: All medi...
Article
Full-text available
ntroduction: There is a need to evaluate the influence of risk factors such as patency of foramen ovale (PFO) or “daredevil” psychological profile on contra-indication policy after a decompression sickness (DCS). Methods: By crossing information obtained from Belgian Hyperbaric Centers, DAN Emergency Hotline, the press and Internet diving forums, i...
Article
Full-text available
BACKGROUND: Divers try to limit risks associated with their sport, for instance by breathing enriched air nitrox (EANx) instead of air. This double blinded, randomized trial was designed to see if the use of EANx could effectively improve cognitive performance while diving. METHODS: Eight volunteers performed two no-decompression dry dives breathi...
Article
Full-text available
Background: Using ultrasound imaging, vascular gas emboli (VGE) are observed after asymptomatic scuba dives and are considered a key element in the potential development of decompression sickness (DCS). Diving is also accompanied with vascular dysfunction, as measured by flow-mediated dilation (FMD). Previous studies showed significant intersubjec...
Article
Full-text available
Purpose: Since non-provocative dive profiles are no guarantor of protection against decompression sickness, novel means including pre-dive “preconditioning” interventions, are proposed for its prevention. This study investigated and compared the effect of pre-dive oxygenation, pre-dive whole body vibration or a combination of both on post-dive bubb...
Article
Full-text available
SCUBA diving exposes divers to decompression sickness (DCS). There has been considerable debate whether divers with a Patent Foramen Ovale of the heart have a higher risk of DCS because of the possible right-to-left shunt of venous decompression bubbles into the arterial circulation. Symptomatic neurological DCS has been shown to cause permanent da...
Article
Full-text available
Decompression sickness (DCS) is a systemic disorder assumed due to gas bubbles, but additional factors are likely to play a role. Circulating microparticles, vesicular structures with diameters of 0.1 to 1.0 µm, have been implicated but data in human divers has been lacking. We hypothesized that the number of blood-borne annexin V-positive micropar...
Article
Full-text available
Diving medicine is a peculiar specialty. There are physicians and scientists from a wide variety of disciplines with an interest in diving and who all practice 'diving medicine': the study of the complex whole-body physiological changes and interactions upon immersion and emersion. To understand these, the science of physics and molecular gas and f...
Article
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The aim of the study was to observe the effects of dark chocolate on endothelial function after scuba diving. Forty-two male scuba divers were divided into two groups: a control (n = 21) and a chocolate group (n = 21). They performed a 33-metres deep scuba-air dive for 20 minutes in a diving pool (Nemo 33, Brussels). Water temperature was 33⁰C. The...
Chapter
Full-text available
The physiology and pathology of decompression have been studied for over 100 years. The procedures that have been developed for preventing decompression sickness and for its treatment have proven to be relatively effective, even though a large number of individual factors – of which many are not sufficiently understood – seem to play a role. Even i...
Book
Full-text available
Decompression illnesses (DCI), or as they are called more scientifically: dysbaric disorders, represent a complex spectrum of pathophysiological conditions with a wide variety of signs and symptoms related to dissolved gas and its subsequent phase change.1,2 Any significant organic or functional dysfunction in individuals who have recently been exp...
Article
Full-text available
'Decompression stress' is commonly evaluated by scoring circulating bubble numbers post dive using Doppler or cardiac echography. This information may be used to develop safer decompression algorithms, assuming that the lower the numbers of venous gas emboli (VGE) observed post dive, the lower the statistical risk of decompression sickness (DCS). C...
Article
The existence of a right-to-left shunt may increase the likelihood of micro-embolism by allowing a flux of bubbles under hyperbaric conditions. The aim of the study was to measure the relationship between these shunts and bubbles in 10 consecutive subjects using trans-thoracic and trans-esophageal echocardiography. In video frames, all cardiac cham...
Article
Full-text available
The aim of this study is to observe the effects of dark chocolate on endothelial function after a series of successive apnea dives in non-thermoneutral water. Twenty breath-hold divers were divided into two groups: a control group (8 males and 2 females) and a chocolate group (9 males and 1 female). The control group was asked to perform a series o...
Article
Full-text available
Measurement of inert gas narcosis and its degree is difficult during operational circumstances, hence the need for a reliable, reproducible and adaptable tool. Although being an indirect measure of brain function, if reliable, critical flicker fusion frequency (CFFF) could address this need and be used for longitudinal studies on cortical arousal i...
Article
Full-text available
Hyperoxia causes oxidative stress. Breath-hold diving is associated with transient hyperoxia followed by hypoxia and a build-up of carbon dioxide (CO₂), chest-wall compression and significant haemodynamic changes. This study analyses variations in plasma oxidative stress markers after a series of repetitive breath-hold dives. Thirteen breath-hold d...
Article
Full-text available
It has been proposed that relative changes of oxygen availability rather than steady state hypoxic or hyperoxic conditions, play an important role in HIF transcriptional effects. According to this hypothesis describing the "normobaric oxygen paradox", normoxia following a hyperoxic event is sensed by tissues as an oxygen shortage, upregulating HIF-...
Article
Full-text available
A novel approach to increasing erythropoietin (EPO) using oxygen (O2) (the 'normobaric oxygen paradox') has been reported in healthy volunteers. We investigated whether the EPO increase is sufficient to induce erythropoiesis by comparing two protocols of O2 administration. We compared the effect of daily versus alternate days 100% O2, breathed for...
Article
Full-text available
Bubble recognition is a challenging problem in a broad range from mechanics to medicine. These gas–filled structures whose pattern and morphology alter in their surrounding environment would be counted either manually or with computational recognition procedures. In cardiology, user dependent bubble detection and temporal counting in videos require...
Conference Paper
2D echocardiography which is the golden standard in clinics becomes the new trend of analysis in diving via its high advantages in portability for diagnosis. By the way, the major weakness of this system is non-integrated analysis platform for bubble recognition. In this study, we developed a full automatic method to recognize bubbles in videos. Ga...
Article
The main limiting factors determining apnea time are generally considered to be related to blood and cerebrospinal fluid chemistry. Several physiological (adaptive) mechanisms and some psychologic parameters, such as motivation, are also known to increase apnea time. We wished to study the link between peripheral muscle fatigue, the concomitant alt...
Article
Full-text available
In cardiology, automatic recognition and image analysis still conserve computational challenges in terms of medical guidance and diagnosis. Bubbles or microemboli that circulate into cardiopulmonary system are considered suspicious for several medical problems such as decompression sickness, stroke and migraine. The aim of our work is to develop an...
Article
Breath-hold diving is both a recreational activity, performed by thousands of enthusiasts in Europe, and a high-performance competitive sport. Several 'disciplines' exist, of which the 'no-limits' category is the most spectacular: using a specially designed heavy 'sled,' divers descend to extreme depths on a cable, and then reascend using an inflat...
Article
Full-text available
The purpose of the study was to analyze the ultrasound lung comets (ULCs) variation, which are a sign of extra-vascular lung water. Forty-two healthy individuals performed breath-hold diving in different conditions: dynamic surface apnea; deep variable-weight apnea and shallow, face immersed without effort (static maximal and non-maximal). The numb...
Article
Full-text available
Many divers report less fatigue following dives breathing enriched air nitrox (EANx) compared with breathing air. A reduction of post-dive fatigue with EANx would suggest a pathological origin, possibly the presence of asymptomatic nitrogen bubbles in the body after a dive. We studied fatigue in 219 healthy divers performing either an air (n = 121)...
Article
Purpose Some patients questioned us whether diving and mountaineering can have an effect on their intraocular pressure (IOP). Since the results in the literature concerning mountaineering are often contradictory and the data concerning diving are very limited; we investigated if an increase in atmospheric pressure influences the IOP in a normal pop...
Article
Full-text available
Impulse noise from firearms is a common cause of acute acoustic trauma (AAT), which is characterized by high-frequency hearing loss and tinnitus. Various treatment modalities have been proposed, some combining medical treatment with hyperbaric oxygen (HBOT) in various ways. We have reviewed the therapeutic effect of primary protocols, with or witho...
Article
Full-text available
The preconditioning of divers to reduce post-dive decompression sickness (DCS) has gained increased interest in diving medical research over the last few years. The beneficial effects of physical exercise, oxygen breathing, hyperbaric exposure, heat exposure, hyperhydration, or nitroglycerin administration before the dive are only a few examples of...
Article
Full-text available
Experience from treating diving accidents indicates that a large proportion of divers suffering from pulmonary barotraumas (PBT) or arterial gas embolism (AGE) were engaged in training dives, specifically emergency free ascent (EFA). We tried to verify this relationship and to calculate, if possible, the risk associated with normal recreational div...
Article
Full-text available
This study investigated the influence of a far infrared-ray dry sauna-induced heat exposure before a simulated dive on bubble formation, and examined the concomitant adjustments in hemodynamic parameters. There were 16 divers who were compressed in a hyperbaric chamber to 400 kPa (30 msw) for 25 min and decompressed at 100 kPa x min(-1) with a 4-mi...
Article
Full-text available
Pulmonary blebs and bullae are generally considered an absolute contra-indication for scuba diving, because of a high estimated risk of pulmonary overpressure syndrome due to air-trapping inside the bulla. This is primarily based on a number of retrospective studies and case reports; formal prospective evidence of a higher risk is lacking. We prese...
Article
To determine whether the atmospheric pressure (ATM) change experienced during diving can induce changes in the intraocular pressure (IOP) of eyes in a normal population. The IOP of 27 healthy volunteers (ages, 23.8 +/- 4.9 years; range, 18-44) was measured with a Perkins applanation tonometer by two independent investigators who were masked to the...
Article
Full-text available
It is claimed that performing a "deep stop," a stop at about half of maximal diving depth (MDD), can reduce the amount of detectable precordial bubbles after the dive and may thus diminish the risk of decompression sickness. In order to ascertain whether this reduction is caused by the deep stop or by a prolonged decompression time, we wanted to te...
Article
Renal (peritubular) tissue hypoxia is a well-known physiological trigger for erythropoietin (EPO) production. We investigated the effect of rebound relative hypoxia after hyperoxia obtained under normo- and hyperbaric oxygen breathing conditions. A group of 16 healthy volunteers were investigated before and after a period of breathing 100% normobar...
Chapter
Full-text available
Hyperbaric oxygen therapy is a relatively recent development in the field of human medicine, and is in many aspects “unproven”, because based on animal and laboratory evidence. An overview is given of the recent developments in research effort, made by the European hyperbaric “community” to work towards this final goal: to stand the test of Evidenc...
Article
Full-text available
Using a standardized contrast-enhanced transesophageal echocardiographic technique, a group of divers was reexamined for the presence and size of patent foramen ovale (PFO) 7 years after their initial examinations. Unexpected but significant increases in the prevalence and size of PFO were found, suggesting a possible increasing risk for decompress...
Article
Patency of the foramen ovale is a risk factor for DCS in SCUBA divers, even if they adhere to the currently accepted and used decompression tables. The primary cause of DCS, however, is the nitrogen bubble, not the PFO. There are a number of techniques any diver can use to minimize the occurrence of nitrogen bubbles after a dive. The authors curren...
Article
Oxygen breathing for a moderate duration promotes tissular denitrogenation; and increases tissular oxygen levels. After cessation of oxygen breathing, nitrogen partial pressure in all body tissues including the renal tissue, will rise to saturation, causing a concomitant decrease of tissular oxygen tension. This "relative" hypoxia may be able to in...

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Archived project
Project
Just starting project on the benefit of Oxygen in different settings